delete pics to save space

2.11440.cpp

@@ -0,0 +1,29 @@
+#include<cstdio>
+#include<cmath>
+const int maxn=10000010,MOD=100000007;
+int vis[maxn],phifac[maxn];
+void init(int n)
+{
+	int m=(int)sqrt(n+0.5),c=0,i,j;
+	for(i=2;i<=m;i++)
+		if(!vis[i])
+			for(j=i*i;j<=n;j+=i) vis[j]=1;
+}
+int n,m,i,res;
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	init(10000000);
+	phifac[1]=phifac[2]=1;
+	for(i=3;i<=10000000;i++)
+		phifac[i]=(long long)phifac[i-1]*(vis[i]?i:i-1)%MOD;
+	while(scanf("%d%d",&n,&m)==2&&m&&n)
+	{
+		res=phifac[m];
+		for(i=m+1;i<=n;i++) res=(long long)res*i%MOD;
+		printf("%d\n",(res-1+MOD)%MOD);
+	}
+	return 0;
+}