比如：

(此图来自网络)

代码如下：

#include<cstdio>
#define ll long long

using namespace std;
ll a[505][505],b[505][505];
const ll mod=1000000007;
ll n,m,p;

inline ll read(){
	ll a=0,k=1;
	char c=getchar();
	while (!('0'<=c&&c<='9')){
		if (c=='-'){
			k*=-1;
		}
		c=getchar();
	}
	while ('0'<=c&&c<='9'){
		a=a*10+c-'0';
		c=getchar();
	}
	return a*k;
}

int main(){
	n=read(),p=read(),m=read();
	for (ll i=1;i<=n;i++){
		for (ll j=1;j<=p;j++){
			a[i][j]=read();
		}
	}
	for (ll i=1;i<=p;i++){
		for (ll j=1;j<=m;j++){
			b[i][j]=read();
		}
	}
	for (ll i=1;i<=n;i++){
		for (ll j=1;j<=m;j++){
			ll tmp=0;
			for (ll k=1;k<=p;k++){
				tmp=(tmp+(a[i][k]*b[k][j]+mod)%mod+mod)%mod;
			}
			printf("%lld ",tmp);
		}
		putchar('\n');
	}
	return 0;
}