import std.stdio, std.conv, std.math, std.string, std.range, std.array,
       std.algorithm;

void main(){
  int[] buf = readln().strip().split().map!(to!int)().array();

  int ans = buf.reduce!min();
  buf[] -= ans;

  for(;;) {
    int maxs, maxp;
    foreach(immutable int i; 0 .. 3) {
      if(maxs < buf[i]) {
        maxs = buf[i];
        maxp = i;
      }
    }

    if(maxs < 3) {
      break;
    } else if(maxs == 3 || maxs == 4) {
      if(buf.reduce!"a + b" - maxs == 0) {
        break;
      } else {
        buf = buf.map!"max(a-1, 0)"().array();
        buf[maxp] -= 2;
        ++ ans;
      }
    } else {
      buf = buf.map!"max(a-1, 0)"().array();
      if(buf.reduce!"a + b" - maxs == 0) {
        buf[maxp] -= 4;
      } else {
        buf[maxp] -= 2;
      }
      ++ ans;
    }
  }

  writeln(ans);
}