public int getMin(int start, int end){
			if(this.start == start && this.end== end) return minVal;
			int mid = (this.start+this.end)/2;
			if(mid>=start && mid>=end) return left.getMin(start, end);
			if(mid<start && mid<end) return right.getMin(start, end);
			return Math.min(left.getMin(start, mid), right.getMin(mid+1, end));
		}