#include <stdio.h>
#define N 300000

int main(void){
    char S[N];
    int n,counter = 0,num = 0,t[N],u;
    scanf("%d",&n);
    scanf("%s",&S);
loop:
    if(S[n-1] == '#'){
        S[n-1] = '.';
    }
    for(int i=0;i<n-1;i++)
    {
        if(S[i] == '#' && S[i+1] == '.')
        {
            S[i] = '.';
            S[i+1] = '#';
            i = i + 1;
        }
    }
    for(int i=0;i<n;i++){
        if(S[i] == '#')
        {
            counter++;
            goto loop;
        }
    }
    counter++;
    goto end;
end:
    printf("%d",counter);
    return 0;
}