const reader = require("readline").createInterface({
  input: process.stdin,
  output: process.stdout
});
let lines = [];
reader.on("line", line => {
  lines.push(line);
});
reader.on("close", () => {
  let votes = lines[1].split(' ').map(str => parseInt(str, 10)).reduce((a, c) => a + c)
  const check = votes.filter(item => item <= sum / 10)
  console.log(30 * check.length)
});