Yogurt-Cucumber (Mast-va-Khiar)

2 cup yogurt
1 cucumber
1 tablespoon raisin
1/2 teaspoon dry mint (or 1 teaspoon well chopped fresh mint)
salt

Beat yougurt with a pinch of salt and then peal cucumber and cut it to small pieces and add it with raisin to yougurt and mix them together.Keep it in refrigrator for half an hour and serve it cold.