whats the mistake...??? (ATM)

#include<stdio.h>
int main()
{
float amt,rmn,f;
int wd;

scanf("%d %f", &wd, &amt);

if(amt<=0 || wd<0)
{
exit(0);
}

if(wd%5==0 && amt>wd && wd>=0)
{
f=(float)wd + 0.50;
rmn=amt-f;
printf("%.2f\n",rmn);
}
else
{
printf("%.2f\n",amt);
}

return 0;
}