#include #define int long long #define REP( i, n ) for( int (i) = 0; (i) < (n); (i)++ ) #define ALL( a ) (a).begin(), (a).end() #define MP make_pair using namespace std; using P = pair; templatebool chmax( T& a, const T& b ) { if( a < b ) { a = b; return 1; } return 0; } templatebool chmin( T& a, const T& b ) { if( a > b ) { a = b; return 1; } return 0; } const int INF = 1e18; const int MOD = 1e9 + 7; int dp[110][20010]; signed main(){ int N, S, K; cin >> N >> S >> K; S -= N * ( N - 1 ) * K / 2; dp[0][0] = 1; for( int i = 1; i <= N; i++ ){ REP( j, S + 1 ){ if( i <= j ){ dp[i][j] = ( dp[i - 1][j] + dp[i][j - i] ) % MOD; }else{ dp[i][j] = dp[i - 1][j]; } } } cout << dp[N][S] << endl; }