const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;
void (async function () {
const arr = (await readline()).split(",").map(Number);
const map = new Map();
let maxLength = arr.length;
let amariLength = arr.length;
for (let i = 0; i < arr.length; i++) {
map.set(arr[i], (map.get(arr[i]) || 0) + 1);
}
const mapArr = [...map.entries()].sort((a, b) => b[1] - a[1]);
let res = 0;
for (const [_, val] of mapArr) {
amariLength -= val;
res++;
if (amariLength <= Math.floor(maxLength / 2)) break;
}
console.log(res);
})();