const readline = require("readline");
const rl = readline.createInterface({
input: process.stdin,
output: process.stdout,
});
let arr = [];
rl.on("line", function (line) {
arr = line.trim().split("");
let count = 0;
for (let i = 0; i < arr.length; i++) {
if (arr[i] === "O") {
count += 1;
}
}
console.log(count);
});