N,S,K=map(int,input().split())
DP=[0]*(S+1)
DP[S]=1

mod=10**9+7
for i in range(N):
    NDP=[0]*(S+1)
    rest=N-i
    for j in range(S+1):
        if i==0:
            if DP[j]!=0:
                NDP[j]+=DP[j]
        else:            
            if DP[j]!=0 and j-rest*K>=0:
                NDP[j-rest*K]+=DP[j]
                NDP[j-rest*K]%=mod

    for j in range(S,-1,-1):
        if j+rest<=S:
            NDP[j]+=NDP[j+rest]
            NDP[j]%=mod
    DP=NDP

print(DP[0])