//at least one that attended ALL dinners//X indicating if attended that dinner (X = 1) or not (X = 0).
#include "stdafx.h"#include <stdio.h>
int a[500][100];
void compare(int number,int dinner){ int i,j; int flag = 0; int count =0;
for(i=0;i<dinner;i++) { for(j=0;j<number;j++) scanf("%d",&a[i][j]); }
for(i=0;i<number;i++) { count = 0; for(j=0;j<dinner;j++) { if(a[j][i] == 1) { count++; if(count == dinner) { flag = 1; break; } } } }
if(flag == 1) printf("yes/n"); else printf("no/n");
}
int main(){ int number,dinner; while(1) { scanf("%d %d",&number,&dinner); if(number ==0 && dinner == 0) break;
compare(number,dinner); }
return 0;}