function processData(input) {
    var seaLevel = valleyCount = 0;
    var startValley = false;
    var steps = input.split('\n')[1].split('');
    steps.forEach(function(step) {
        seaLevel += (step === 'U' ? 1 : -1);
        if(seaLevel == -1) {
            startValley = true;
        }
        if(seaLevel == 0 && startValley) {
            startValley = false;
            valleyCount++;
        }
    });
    console.log(valleyCount);
} 

process.stdin.resume();
process.stdin.setEncoding("ascii");
_input = "";
process.stdin.on("data", function (input) {
    _input += input;
});

process.stdin.on("end", function () {
   processData(_input);
});