#include using namespace std; #define REP(i,a,n) for(int i=(a); i<(int)(n); i++) #define rep(i,n) REP(i,0,n) #define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it) #define ALLOF(c) (c).begin(), (c).end() typedef long long ll; typedef unsigned long long ull; int field[1000][1000]; int main(){ int W, H, X; cin >> W >> H >> X; if(X > 36){ cout << -1 << endl; return 0; } int a,b,c,d; if(X == 36){ a = b = c = d = 9; }else{ a = X%9; b = c = d = (X-a)/3; } for(int i=0; i