#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#define PI 3.141592
int main()
{
	float x, rad = (PI / 180), *num = (float*)malloc(sizeof(float));
	if (num == NULL)
	{
		puts("Error: failed to allocate memory.");
		return;
	}
	int count = 0;
	char ch;
	while (1)
	{
	finish:
		if (count > 0)
		{
			scanf(" %f", &num[count]);
			if (ch == '-')
			{
				num[count] = (num[count - 1] - num[count]);
				printf("%f\n", num[count]);
			}
			else if (ch == '+')
			{
				num[count] = (num[count - 1] + num[count]);
				printf("%f\n", num[count]);
			}
			else if (ch == ':')
			{
				num[count] = (num[count - 1] / num[count]);
				printf("%f\n", num[count]);
			}
			else if (ch == '*')
			{
				num[count] = (num[count - 1] * num[count]);
				printf("%f\n", num[count]);
			}
		}
		else
		{
			num[count] = 0;
			scanf(" %f", &num[count]);
		}
	here:
		scanf(" %c", &ch);
		switch (ch)
		{
		case'-':
			count++;
			num = (float*)realloc(num, sizeof(float)*(count + 1));
			if (num == NULL)
			{
				puts("Error: failed to allocate memory.");
				exit(1);
			}
			goto finish;
		case'+':
			count++;
			num = (float*)realloc(num, sizeof(float)*(count + 1));
			if (num == NULL)
			{
				puts("Error: failed to allocate memory.");
				exit(1);
			}
			goto finish;
		case':':
			count++;
			num = (float*)realloc(num, sizeof(float)*(count + 1));
			if (num == NULL)
			{
				puts("Error: failed to allocate memory.");
				exit(1);
			}
			goto finish;
		case'*':
			count++;
			num = (float*)realloc(num, sizeof(float)*(count + 1));
			if (num == NULL)
			{
				puts("Error: failed to allocate memory.");
				exit(1);
			}
			goto finish;
		case's':
			scanf(" %f", &x);
			num[count] = sin(x*rad);
			printf("%f\n", num[count]);
			goto here;
		case'c':
			scanf(" %f", &x);
			num[count] = cos(x*rad);
			printf("%f\n", num[count]);
			goto here;
		case't':
			scanf(" %f", &x);
			if (x == 90)
				puts("Error: no such value.");
			else
			{
				num[count] = (sin(x*rad) / cos(x*rad));
				printf("%f\n", num[count]);
			}
			goto here;
		case'l':
			scanf(" %f", &x);
			num[count] = log10(x);
			printf("%f", num[count]);
			goto here;
		case'e':
			scanf(" %f", &x);
			num[count] = exp(x);
			printf("%f\n", num[count]);
			goto here;
		case'/':
			num[count] = sqrt(num[count]);
			printf("%f\n", num[count]);
			goto here;
		case'^':
			scanf(" %f", &x);
			num[count] = pow(num[count], x);
			printf("%f\n", num[count]);
			goto here;
		case'D':
			for (int i = count; i >= 0; i--)
				num[i] = num[i + 1];
			num = (float*)realloc(num, sizeof(float));
			if (num == NULL)
			{
				puts("Error: failed to allocate memory.");
				exit(1);
			}
			count = 0;
			goto finish;
		case'Q':
			exit(0);
		default:
			puts("Error: no such char.");
			exit(1);
		}
	}
}