import std.stdio, std.array, std.string, std.conv, std.algorithm; import std.typecons, std.range, std.random, std.math, std.container; import std.numeric, std.bigint, core.bitop, std.bitmanip, std.regex; void main() { auto N = readln.chomp.to!int; auto S = readln.chomp; auto A = new long[][](N, 3); foreach (i; 0..N) { if (i > 0) foreach (j; 0..3) A[i][j] = A[i-1][j]; if (S[i] == '(') A[i][2] += 1; else if (S[i] == ')' && A[i][2] > 0) A[i][2] -= 1, A[i][1] += 1; else A[i][0] += 1; } long ans = 0; foreach (i; 0..N) ans += A[i][1] * 2; A.sort!"a[0] < b[0]"; long a = 0; foreach (i; 0..N) { long m = min(a, A[i][0]); ans += m * 2; a -= m; a += A[i][2]; } ans.writeln; }