Alerting: Need to look for a string (string1) and a second string (string2) right after a minute.

we need to look for a string (string1) on all server logs. And if that string1 is detected, then we need to look for a second string (string2) in the next 1 minute. Usually it would be within few seconds, so 1 minute would give ample buffer time. If the second message (string2) is not found within that 1 minute after the first string (string1) is found, then it should trigger an alert and send to your email.