(2)

#include<stdio.h>

int main(void){
char *s, *t;
int c = 0;
unsigned char data[2][256];
int h[2] = {-1,-1};
int i = 0;
while (gets(data[i]) != NULL){
h[i] = 0;
for(s = data[i];*s;s++) h[i] = h[i] * 137 + *s;
h[i] %= 1987;
c = (h[i] != h[i^1]);
if(!c) for(s=data[i],t=data[i^1];*s && *t;s++,t++) if(*s != *t){ c = 1; break; }
if(c){
puts(data[i]);
i ^= 1;
}
}
return 0;
}