import std.conv, std.functional, std.range, std.stdio, std.string; import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons; import core.bitop; class EOFException : Throwable { this() { super("EOF"); } } string[] tokens; string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; } int readInt() { return readToken.to!int; } long readLong() { return readToken.to!long; } real readReal() { return readToken.to!real; } bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } } bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } } int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; } int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); } int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); } void main() { try { for (; ; ) { const N = readInt; const S = readToken; int[3][3] A; foreach (i; 0 .. 3 * N) { const x = "con".indexOf(S[i]); if (~x) { ++A[i % 3][x]; } } debug { writeln("A = ", A); } int ans; { int score = min(A[0][0], A[1][1], A[2][2]); debug { writeln("score = ", score); } chmax(ans, score); } { int score; foreach (j; 0 .. 3) { int mn = int.max; foreach (x; 0 .. 3) { chmin(mn, A[(j + x) % 3][x]); } score += mn; } chmin(score, N - 1); debug { writeln("score = ", score); } chmax(ans, score); } writeln(ans); } } catch (EOFException e) { } }