#include #include #include #include #include #include #include #include #include #include #define rep(i,n) for(int i=0;i=0;i--) #define FOR(i,a,b) for(int i=a;i>n; vector a; a.resize(n+1); a[1]=1; a[2]=2; a[3]=6; a[4]=28; FOR(i,5,n+1){ a[i]=i*(a[i-2]/(i-2)+a[i-1])%1000000007; a[i]=a[i]%1000000007; } cout<