#include <iostream>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,b) FOR(i,0,b)
using namespace std;
typedef long long LL;
LL DP[101][20001];
LL sum[22001];
const LL p=7+1e+9;
int main() {
	LL N,S,K;
	cin >> N >> S >> K;
	DP[0][0]=1;
	LL c=0;
	FOR(i,1,N+1){
		LL suv=(N-i+1);
		REP(j,S+1) sum[j]=DP[i-1][j];
		REP(j,S+1) sum[j+suv]+=sum[j];
		FOR(j,c*suv,S+1) DP[i][j]=sum[j-c*suv];
		REP(j,S+1) DP[i][j]%=p;
		c=K;
	}
	cout << DP[N][S] << endl;
	// your code goes here
	return 0;
}