#include <bits/stdc++.h>
using namespace std;
const int oo = 1 << 20;
const double PI = M_PI;
const double EPS = 1e-15;
int A, B, C, D;
int main() {
  cin >> A >> B >> C >> D;
  if (C == D) {
    int a = A - (C + 1), b = B - C;
    if (a >= 0 && b >= 0) {
      for (int i = 0; i < a; i++) cout << 4;
      for (int i = 0; i < C; i++) cout << 47;
      for (int i = 0; i < b; i++) cout << 7;
      cout << 4 << endl;
      return 0;
    }
    a = A - C, b = B - (C + 1);
    if (a >= 0 && b >= 0) {
      cout << 74;
      for (int i = 0; i < a; i++) cout << 4;
      for (int i = 0; i < C - 1; i++) cout << 74;
      for (int i = 0; i < b + 1; i++) cout << 7;
      return 0;
    }
    cout << -1 << endl;
    return 0;
  }
  if (abs(C - D) > 1) {
    cout << -1 << endl;
    return 0;
  }
  if (C > D) {
    A = A - C;
    B = B - C;
    if (A < 0 || B < 0) {
      cout << -1;
      return 0;
    }
    for (int i = 0; i < A; i++) cout << 4;
    for (int i = 0; i < C; i++) cout << 47;
    for (int i = 0; i < B; i++) cout << 7;
    return 0;
  } else {
    A = A - D + 1;
    B = B - D + 1;
    if (A <= 0 || B <= 0) {
      cout << -1;
      return 0;
    }
    cout << 7;
    for (int i = 0; i < A; i++) cout << 4;
    for (int i = 0; i < D - 2; i++) cout << 74;
    for (int i = 0; i < B; i++) cout << 7;
    cout << 4;
    return 0;
  }
  cout << -1 << endl;
  return 0;
}
