#include #define rep(i,n) for(int i=0;i<(int)(n);++i) #define rep1(i,a,n) for(int i=(int)a;i<(int)n;++i) #define fi first #define se second #define PI 3.14159265359 using namespace std; using ll=long long; using pii=pair; using pll=pair; using veci=vector; using vecii=vector>; using vecll=vector; using vecpll=vector>; using vecs=vector; using vecb=vector; using vecd=vector; template inline bool chmax(T& a,T b){if(a inline bool chmin(T& a,T b){if(a>b) {a=b;return true;} return false;} constexpr int INF=1<<30; //constexpr ll INF=1LL<<61; //constexpr int MOD=1000000007; constexpr ll MOD=1000000007; //constexpr ll MOD=998244353; //constexpr int LOG=62; int main(){ //ifstream in("input.txt"); //cin.rdbuf(in.rdbuf()); ll n,s,k;cin>>n>>s>>k; s-=n*(n-1)*k/2; if(s<=0) { cout<<0< dp(s+1,vecll(n+1,0)); rep(i,n+1) dp[0][i]=1; rep1(i,1,s+1) rep1(j,1,n+1){ dp[i][j]=dp[i][j-1]+(i>=j?dp[i-j][j]:0); dp[i][j]%=MOD; } cout<