public class RGBStreet {
	private const int MAX_INT = 1005 * 25;

	private int[] ConvertToArr(string house) {
		var arr = new int[3];
		var strArr = house.Split(' ');
		for (int i=0;i<strArr.Length;i++) {
			arr[i] = int.Parse(strArr[i]);
		}
		return arr;
	}

	private int Min(int a, int b) {
		return a < b ? a : b;
	}

	public int estimateCost(string[] houses) {
		var dp = new int[houses.Length][];
		for (int i=0;i<houses.Length;i++) {
			dp[i] = new int[3];
			for (int j=0;j<dp[i].Length;j++) {
				dp[i][j] = MAX_INT;
			}
		}

		int[] values = ConvertToArr(houses[0]);
		dp[0][0] = values[0];
		dp[0][1] = values[1];
		dp[0][2] = values[2];
		for (int i=1;i<houses.Length;i++) {
			values = ConvertToArr(houses[i]);
			for (int k=0;k<3;k++) {
				dp[i][k] = Min(dp[i-1][(k-1+3)%3], dp[i-1][(k+1+3)%3]) + values[k];
			}
		}
		return Min(dp[houses.Length-1][0], Min(dp[houses.Length-1][1], dp[houses.Length-1][2]));
	}
}