ll f[16]={1}; rep(i,1,16)f[i]=f[i-1]*i; ll@n,@m; ll a[16]={0,1}; ll b[16]; rep(i,2,16){ ll z=0; rep(j,i){ z+=f[i]/(f[j]*f[i-j])*a[j]; } a[i]=i**n-z; } wt(a[m]);