diff --git a/du4/test b/du4/test
new file mode 100755
index 0000000..db023eb
Binary files /dev/null and b/du4/test differ
diff --git a/du4/test.c b/du4/test.c
new file mode 100644
index 0000000..66d3268
--- /dev/null
+++ b/du4/test.c
@@ -0,0 +1,57 @@
+#include <stdio.h>
+#include <stdbool.h>
+
+int main ()
+{
+	int c, vysledok, i = 0;
+	int b[99];
+	bool first = true;
+	bool second = false;
+	while(1){
+		c = getchar();
+		if(c <= 255 && c >= 0){
+			if(c == '\n'){
+				break;
+			}else if(c == ' '){
+				continue;
+			}else if(c == '='){
+				continue;
+			}else if(c == '+'){
+				first = true;
+				second = true;
+				continue;
+			}else if(c == '-'){
+				first = false;
+				second = false;
+				continue;
+			}else if(c == '/'){
+				first = true;
+				second = false;
+				continue;
+			}else if(c == '*'){
+				first = false;
+				second = true;
+				continue;
+			}
+		}else{
+			if(i == 2)
+				break;
+			c = 0;
+			int r = scanf("%d",&c);
+			b[i++] = c;
+		}
+	}
+	if(first == true && second == true)
+		vysledok = b[0] + b[1];
+	else if(first == false && second == false)
+		vysledok = b[0] - b[1];
+	else if(first == true && second == false)
+		vysledok = b[0] / b[1];
+	else if(first == false && second == true)
+		vysledok = b[0] * b[1];
+	if(vysledok == b[2])
+		printf("OK\n");
+	else
+		printf("ZLE\n");
+	return 0;
+}