import math l = int(input()) f = input() res = 0 for flsqrt in range(3, int(math.sqrt(l)) +1): fl = flsqrt ** 2 smallcount = (flsqrt - 2) ** 2 bigcount = fl - smallcount xs = 0 s = [] i = 0 for c in range(fl): s.append(f[c]) if f[c] == 'X': xs += 1 if (xs == smallcount and fl - xs == bigcount) or (xs == bigcount and fl - xs == smallcount): res += 1 for c in range(fl, l): if f[c] != s[i]: if f[c] == 'X': xs += 1 else: xs -= 1 s[i] = f[c] if (xs == smallcount and fl - xs == bigcount) or (xs == bigcount and fl - xs == smallcount): res += 1 i += 1 if i == fl: i = 0 print(res)