#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int uint;
typedef pair<int,int> pii;
const int maxn=2e5+7;
const ll modn=1e9+7;
const int inf=2e9+7;
const double PI = acos(-1.0);
const double eps=1e-8;
inline int lowbit(int x){return x&-x;}
inline ll lowbit(ll x) {return x&-x;}
inline int CountOneBinary(ll num){int ans=0;while(num){if(num&1) ans+=1;num>>=1;}return ans;}
inline void read(int &x){char c;x=0;for(c=getchar();c>'9'||c<'0';c=getchar());for(;c>='0'&&c<='9';c=getchar()) x=x*10+c-'0';}
inline void read(ll &x){char c;x=0;for(c=getchar();c>'9'||c<'0';c=getchar());for(;c>='0'&&c<='9';c=getchar()) x=x*10+c-'0';}
inline ll qpow(ll x,ll y){ll ans=1;while(y){if(y&1) ans=ans*x%modn;x=x*x%modn;y>>=1;}return ans;}
inline double qpow(double x,ll y){double ans=1;while(y){if(y&1) ans=ans*x;x=x*x;y>>=1;}return ans;}
ll inv[maxn],h,w,a,b;
inline ll C(ll x,ll y)
{
    x=min(x,y-x);
    ll ans=1;
    for(ll up=y,down=1;down<=x;down++,up--) ans=ans*up%modn*inv[down]%modn;
    return ans;
}
int main()
{
    for(ll i=1;i<maxn;i++) inv[i]=qpow(i,modn-2);
    while(scanf("%lld%lld%lld%lld",&h,&w,&a,&b)==4)
    {
        ll ans=C(h-1,w+h-2);
        ll left=C(w-b-1,a+w-b-2),right=C(b-1,h-a+b-1);
        while(a)
        {
            ans=((ans-left*right%modn)%modn+modn)%modn;
            left=left*(a-1)%modn*inv[a+w-b-2]%modn;
            right=right*(h-a+b)%modn*inv[h-a+1]%modn;
            a--;
        }
        printf("%lld\n",ans);
    }
}

#pragma GCC optimize("O3")
#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
using namespace std;
using base = complex<double>;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define M 1000000007
#define M2 998244353
#define ll long long
#define pll pair<long, long>
#define REP(i, a, b) for (ll i = a; i < b; i++)
#define REPI(i, a, b) for (ll i = b - 1; i >= a; i--)
#define ff first
#define ss second
#define pb push_back
#define db pop_back
#define mp make_pair
#define mt make_tuple
#define g(a, b) get<a>(b)
#define INF (ll)1e18 + 100
#define vl vector<ll>
#define vi vector<int>
#define vll vector<pair<ll, ll>>
#define vii vector<pair<int, int>>
#define all(v) v.begin(), v.end()
#define bset(a, p) ((a) | (1ll << (p)))
#define bchk(a, p) ((a) & (1ll << (p)))
#define bxor(a, p) ((a) ^ (1ll << (p)));
#define brem(a, p) (bchk(a, p) ? (bxor(a, p)) : (a))
#define INT_SIZE 32
/*SOME BITMASK KNOWLEDGE
1)x & (x - 1):sets the last one bit of x to zero
power of two exactly when x & (x − 1) = 0.
2)x & -x:sets all the one bits to zero, except last one bit
3)x | (x - 1):inverts all the bits after the last one bit*/

#define o_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
#define o_setll tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update>
//member functions :
//1. order_of_key(k) : number of elements strictly lesser than k
//2. find_by_order(k) : k-th element in the set
ll powM(ll x, ll y, ll m)
{
    ll ans = 1, r = 1;
    x %= m;
    while (r > 0 && r <= y)
    {
        if (r & y)
        {
            ans *= x;
            ans %= m;
        }
        r <<= 1;
        x *= x;
        x %= m;
    }
    return ans;
}
ll modI(ll a, ll m)
{
    ll m0 = m, y = 0, x = 1;
    if (m == 1)
        return 0;
    while (a > 1)
    {
        ll q = a / m;
        ll t = m;
        m = a % m;
        a = t;
        t = y;
        y = x - q * y;
        x = t;
    }
    if (x < 0)
        x += m0;
    return x;
}

ll logint(ll x, ll y)
{
    ll ans = 0;
    ll a = 1;
    for (ll i = 0; i <= x; i++)
    {
        if (x < a)
        {
            return ans;
        }
        ans++;
        a *= y;
    }
    return -1;
}
ll extended(ll a, ll b, ll &x, ll &y)
{
    if (a == 0)
    {
        x = 0;
        y = 1;
        return b;
    }
    ll x1, y1;
    ll d = extended(b % a, a, x1, y1);
    x = y1 - (b / a) * x1;
    y = x1;
    return d;
}
ll lcm(ll x, ll y) {
    return (x * y) / (__gcd(x, y));
}

void solve() {
    ll sx, sy, tx, ty;
    cin >> sx >> sy >> tx >> ty;
    // int c = 0;
    REP(j, sx, tx) {
        cout << 'R';
        // c++;
    }
    REP(j, sy, ty) {
        cout << 'U';
        // c++;
    }
    REP(j, sx, tx) {
        cout << 'L';
        // c++;
    }
    REP(j, sy, ty) {
        cout << 'D';
        // c++;
    }
    cout << 'D';
    // c++;
    REP(j, sx, tx) {
        cout << 'R';
        // c++;
    }
    // c++;
    cout << 'R';
    REP(j, sy, ty) {
        // c++;

        cout << 'U';
    }
    cout << 'U';
    cout << 'L';
    cout << 'U';
    // c++;
    // c++;
    // c++;

    REP(j, sx, tx) {
        // c++;
        cout << 'L';
    }
    // c++;
    cout << 'L';
    REP(j, sy, ty) {
        cout << 'D';
    }
    cout << 'D';
    cout << 'R';
    // string temp = "UURRURRDDDLLDLLULUUURRURRDDDLLDL";
    // cout << temp.size() << " " << c;
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    // freopen("b1.in", "r", stdin);
    // freopen("output.txt", "w", stdout);
    ll ntc;
    // cin >> ntc;
    ntc = 1;
    REP(tc, 1, ntc + 1)
    {
        // cout << "Case #" << tc << ": ";
        solve();
    }
}

