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)); }


int N;

int ans;
int[][] col;
int[][][] cnt;

void dfs(int x, int y) {
  if (y == N) {
    ++x;
    y = 0;
    chmax(ans, x);
  }
  foreach (c; 0 .. 2) {
    bool ok = true;
    foreach (yy; 0 .. y) if (col[x][yy] == c) ok = ok && (cnt[c][yy][y] == 0);
    if (ok) {
      foreach (yy; 0 .. y) if (col[x][yy] == c) ++cnt[c][yy][y];
      col[x][y] = c;
      dfs(x, y + 1);
      foreach (yy; 0 .. y) if (col[x][yy] == c) --cnt[c][yy][y];
    }
  }
}

void main() {
  try {
    for (; ; ) {
      N = cast(int)(min(readLong(), 10^^9));
      if (N <= 2) {
        writeln("INF");
      } else {
        ans = 2;
        if (N <= 6) {
          col = new int[][](7, N);
          cnt = new int[][][](2, N, N);
          dfs(0, 0);
        }
        writeln(ans);
      }
    }
  } catch (EOFException e) {
  }
}