#include <bits/stdc++.h>
using namespace std;
int a, b, c, d;
char s[3000007];
void case1() {
  int now = 0;
  for (int i = 0; i < a - c; ++i) s[now++] = '4';
  for (int i = 0; i < c; ++i) s[now++] = '4', s[now++] = '7';
  for (int i = 0; i < b - c; ++i) s[now++] = '7';
  s[now] = 0;
}
void case2() {
  int now = 0;
  s[now++] = '7', s[now++] = '4';
  for (int i = 0; i < a - d; ++i) s[now++] = '4';
  for (int i = 0; i < d - 2; ++i) s[now++] = '7', s[now++] = '4';
  for (int i = 0; i < b - d; ++i) s[now++] = '7';
  s[now++] = '7', s[now++] = '4';
  s[now] = 0;
}
void case3() {
  int now = 0;
  for (int i = 0; i < a - d; ++i) s[now++] = '4';
  for (int i = 0; i < d - 1; ++i) s[now++] = '7', s[now++] = '4';
  for (int i = 0; i < b - d; ++i) s[now++] = '7';
  s[now++] = '7', s[now++] = '4';
  s[now] = 0;
}
void case4() {
  int now = 0;
  s[now++] = '7', s[now++] = '4';
  for (int i = 0; i < a - d; ++i) s[now++] = '4';
  for (int i = 0; i < d - 1; ++i) s[now++] = '7', s[now++] = '4';
  for (int i = 0; i < b - d; ++i) s[now++] = '7';
  s[now] = 0;
}
int main() {
  cin >> a >> b >> c >> d;
  if (c == d + 1 && b >= c && a >= c) {
    case1();
    cout << s << endl;
    return 0;
  }
  if (d == c + 1 && a >= d && b >= d) {
    case2();
    cout << s << endl;
    return 0;
  }
  if (c == d && b >= d && a >= d + 1) {
    case3();
    cout << s << endl;
    return 0;
  }
  if (c == d && b >= d + 1 && a >= d) {
    case4();
    cout << s << endl;
    return 0;
  }
  cout << -1 << endl;
  return 0;
}
