code is:
#include <stdio.h>
int main(void)
{
int t;
scanf("%d",&t);
while(t--)
{
int d,i,count=0,preq=0,ppos=0;
double a;
scanf("%d",&d);
//fflush(stdin);
char str[d+1];
scanf("%s",str);
//fflush(stdin);
for(i=0;i<=d-1;i++)
{
if(str[i]=='P')
count++;
}
//printf("count of p=%d\n",count);
//if(count/(d*1.00)>=0.75)
//{
//printf("0\n");
//}
if(count/(d*1.00)<0.75)
{
a=d*(0.75-count/(d*1.00));
preq=ceil(a);
}
//printf("preq=%d\n",preq);
for(i=2;i<=d-3;i++)
{
if(str[i]=='A')
{
if(str[i-1]=='P'||str[i-2]=='P')
{
if(str[i+1]=='P'||str[i+2]=='P')
ppos++;
}
}
}
// printf("ppos=%d\n",ppos);
if(preq<=ppos)
printf("%d\n",preq);
if(preq>ppos)
printf("-1\n");
}
return 0;
}