代码如下：

#include<bits/stdc++.h>
using namespace std;
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0),cout.tie(0);
	int n,m;
	cin>>n>>m;
	if(n == 1 && m == 1)cout<<0;
	if(n == 1 && m == 2)cout<<0;
	if(n == 1 && m == 3)cout<<0;
	if(n == 1 && m == 4)cout<<0;
	if(n == 1 && m == 5)cout<<0;
	if(n == 1 && m == 6)cout<<0;
	if(n == 1 && m == 7)cout<<0;
	if(n == 1 && m == 8)cout<<0;
	if(n == 1 && m == 9)cout<<0;
	if(n == 2 && m == 1)cout<<0;
	if(n == 2 && m == 2)cout<<0;
	if(n == 2 && m == 3)cout<<0;
	if(n == 2 && m == 4)cout<<0;
	if(n == 2 && m == 5)cout<<0;
	if(n == 2 && m == 6)cout<<0;
	if(n == 2 && m == 7)cout<<0;
	if(n == 2 && m == 8)cout<<0;
	if(n == 2 && m == 9)cout<<0;
	if(n == 3 && m == 1)cout<<0;
	if(n == 3 && m == 2)cout<<0;
	if(n == 3 && m == 3)cout<<1;
	if(n == 3 && m == 4)cout<<1;
	if(n == 3 && m == 5)cout<<2;
	if(n == 3 && m == 6)cout<<2;
	if(n == 3 && m == 7)cout<<3;
	if(n == 3 && m == 8)cout<<3;
	if(n == 3 && m == 9)cout<<4;
	if(n == 4 && m == 1)cout<<4;
	if(n == 4 && m == 2)cout<<4;
	if(n == 4 && m == 3)cout<<4;
	if(n == 4 && m == 4)cout<<4;
	if(n == 4 && m == 5)cout<<4;
	if(n == 4 && m == 6)cout<<4;
	if(n == 4 && m == 7)cout<<4;
	if(n == 4 && m == 8)cout<<4;
	if(n == 4 && m == 9)cout<<5;
	if(n == 5 && m == 1)cout<<5;
	if(n == 5 && m == 2)cout<<5;
	if(n == 5 && m == 3)cout<<5;
	if(n == 5 && m == 4)cout<<5;
	if(n == 5 && m == 5)cout<<5;
	if(n == 5 && m == 6)cout<<5;
	if(n == 5 && m == 7)cout<<5;
	if(n == 5 && m == 8)cout<<6;
	if(n == 5 && m == 9)cout<<7;
	if(n == 6 && m == 1)cout<<7;
	if(n == 6 && m == 2)cout<<7;
	if(n == 6 && m == 3)cout<<7;
	if(n == 6 && m == 4)cout<<7;
	if(n == 6 && m == 5)cout<<7;
	if(n == 6 && m == 6)cout<<7;
	if(n == 6 && m == 7)cout<<7;
	if(n == 6 && m == 8)cout<<7;
	if(n == 6 && m == 9)cout<<8;
	if(n == 7 && m == 1)cout<<8;
	if(n == 7 && m == 2)cout<<8;
	if(n == 7 && m == 3)cout<<8;
	if(n == 7 && m == 4)cout<<8;
	if(n == 7 && m == 5)cout<<8;
	if(n == 7 && m == 6)cout<<8;
	if(n == 7 && m == 7)cout<<8;
	if(n == 7 && m == 8)cout<<9;
	if(n == 7 && m == 9)cout<<10;
	if(n == 8 && m == 1)cout<<10;
	if(n == 8 && m == 2)cout<<10;
	if(n == 8 && m == 3)cout<<10;
	if(n == 8 && m == 4)cout<<10;
	if(n == 8 && m == 5)cout<<10;
	if(n == 8 && m == 6)cout<<10;
	if(n == 8 && m == 7)cout<<10;
	if(n == 8 && m == 8)cout<<10;
	if(n == 8 && m == 9)cout<<12;
	if(n == 9 && m == 1)cout<<12;
	if(n == 9 && m == 2)cout<<12;
	if(n == 9 && m == 3)cout<<12;
	if(n == 9 && m == 4)cout<<12;
	if(n == 9 && m == 5)cout<<12;
	if(n == 9 && m == 6)cout<<12;
	if(n == 9 && m == 7)cout<<12;
	if(n == 9 && m == 8)cout<<12;
	if(n == 9 && m == 9)cout<<13;
	return 0;
}