#include <cstdio>
using namespace std;
int main()
{
int N, l=0, m=0;
char x;
scanf("%d",&N);
scanf("%c",&x);
while(N--)
{
scanf("%c",&x);
if(x=='S') l++;
else
{
m=(m>l)?m:l;
l=0;
}
//printf("%c %d\n",x,l);
}
m=(m>l)?m:l;
printf("%d",m);
return 0;
}
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