function processData(input) {
    const actions = input.split('\n')[1].split('');
    const SEA_LEVEL = 0;
    let isBelowSeaLevel = false;
    let valleys = 0;
    let currentLevel = SEA_LEVEL;
    
    actions.forEach(function(action) {
        if(action === 'D') {
            currentLevel--;
        } else {
            currentLevel++;
        }
        
        if(currentLevel < SEA_LEVEL && isBelowSeaLevel === false) {
            isBelowSeaLevel = true;
            valleys++;
        } else if(currentLevel >= SEA_LEVEL) {
            isBelowSeaLevel = false;
        }
    });
    
    console.log(valleys);
} 

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

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