/*
#include <stdio.h>
#include <stdlib.h>
int main()
{
printf("Hello world!\n");
return 0;
}
*/
/*
#include<stdio.h>
int main()
{
int a,b;
scanf ("%d %d",&a,&b);
}
*/
/*
#include<stdio.h>
int main()
{
int k[51][51] = {0},o[51][51] = {0};
int n,m,a,b;
int i,j;
scanf ("%d %d",&n,&m);
for(i=0; i<m; i++)
{
scanf ("%d %d",);
}
for()
{
}
}
*/