求助我这样写为啥不对啊……

#include<stdio.h>
int main(void)
{
int a = 0,b =0,c =0,d =0;
scanf("%d%d%d%d",&a,&b,&c,&d);
while(a <= 21252 && b<=21252&&c<=21252)
{
a += 23;
b += 28;
c += 33;
if(a == b && b == c)
{
printf("%d\n",a-d);
break;
}
}
return 0;
}