A coin is tossed M+N times,M>N,then the chance of getting at least consecutive head is ??

Let M be an an event of getting at least consecutive head.

∴Probability (getting at least M consecutive heads) =

Probability(getting consecutive heads in first M tosses) + 

Probability(getting tail in the first toss, getting at least M consecutive heads second toss onwards) +

Probability(getting tail in the second toss, getting at least M consecutive heads third toss onwards) + 
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Probability(getting tail in the Nth toss, getting M consecutive heads in last M tosses)