#include <bits/stdc++.h>
#define MOD 1000000007
using namespace std;

int n,s,k;
int dp[101][20001];

int rek(int cur,int sc){
    if(cur==0 && sc==0)
        return 1;
    if(cur<0)
        return 0;
    if(sc<0)
        return 0;
    if(dp[cur][sc]==-1){
        dp[cur][sc]=(rek(cur-1,sc-(n-cur)*k)+rek(cur,sc-(n-cur)))%MOD;
    }
    return dp[cur][sc];
}


int main()
{
    memset(dp,-1,sizeof(dp));
    cin>>n>>s>>k;
    cout<<rek(n-1,s);
    return 0;
}