'use strict';

function main(stdin) {
  const input = stdin.split('').map(s => s === 'o' ? 1 : 0);
  const wins = new Array(15).fill(1);

  input.forEach((s, i) => {
    wins[i] = s;
  });

  if (wins.filter(s => s === 0).length >= 8) {
    console.log('NO');
  } else {
    console.log('YES');
  }  
}

main(require('fs').readFileSync('/dev/stdin', 'utf8'));